Field of the Invention
The present invention relates generally to implantable medical devices, and more particularly, to the configuration of implantable medical devices.
Related Art
Implantable medical devices have become more commonplace as their therapeutic benefits become more widely accepted and the impact and risk of their use have been managed. Many such medical devices include one or more implantable components, collectively referred to as an implantable assembly, and one or more external components, collectively referred to as an external assembly.
In some devices, the external and implanted components are communicably linked by a communication link, such as an RF or inductive link, to provide the required functionality. Although the following will often refer to a particular category of implantable medical devices, namely implantable prosthetic hearing devices known as cochlear implants, it is to be understood that the following is applicable to other types of implantable medical devices such as spinal, visual or other neural stimulators, and medical devices developed for other applications, including those medical implant applications which help to diagnose, monitor, regulate or treat conditions within a recipient's body in which components of the medical device is implanted.
Within the context of prosthetic hearing devices, such implantable medical devices may be beneficially used to treat hearing loss. Hearing loss is generally of two types, conductive and sensorineural. The treatment of both types of hearing loss has been quite different, relying on different principles to enable sound percepts to be generated in a recipient's brain. Conductive hearing loss occurs when the normal mechanical pathways for sound to reach the hair cells in the cochlea are impeded, for example, by damage to the ossicles. In such recipients, hearing is often improved with the use of conventional hearing aids. Such hearing aids amplify sound so that acoustic information reaches the hair cells of the cochlea. Typically, conventional hearing aids utilize acoustic mechanical stimulation, whereby the sound is amplified according to a number of varying techniques, and delivered to the inner ear as mechanical energy. This may be, for example, through a column of air to the eardrum, or through direct delivery to the ossicles of the middle ear.
Sensorineural hearing loss is due to the absence or destruction of the cochlear hair cells which are needed to transduce acoustic signals into auditory nerve impulses. Individuals suffering from this type of hearing loss are unable to derive any benefit from conventional hearing aids regardless of the magnitude of the acoustic mechanical stimulus. In such cases, Cochlear™ implants (also referred to as Cochlear™ devices, Cochlear™ prostheses, Cochlear™ implant systems, and the like; simply “cochlear implants” herein) have been developed to provide hearing percepts in such individuals. Cochlear implants provide electrical stimulation via stimulating electrodes positioned as close as possible to the nerve endings of the auditory nerve, essentially bypassing the cochlear hair cells. The application of a stimulation pattern to the nerve endings causes impulses to be sent to the brain via the auditory nerve, resulting in the brain perceiving the impulses as sound.
Conventional cochlear implants employ one or more implanted components as well as one or more external components. External components include, for example, a microphone and a speech processor. Internal components include, for example, an electrode carrier member for implantation in the cochlea to position an array of electrodes or contacts in the cochlea, and a stimulator unit which generates and delivers electrical stimulation signals to the electrodes.
In conventional medical devices, including the conventional cochlear implants noted above, one or more of the external components are typically configured, or customized, for operation with a specific recipient. Such customization is typically achieved by deriving a set of instructions or settings values for that recipient, referred to as recipient-specific operating parameters, and storing those parameters in the customizable external component. The recipient-specific operating parameters are then used by the external component to perform operations for that recipient. In the cochlear implant application introduced above, such operations include, for example, processing received sounds in a specific manner that is optimized or “fitted” for the particular recipient. For cochlear implants, these settings values or instructions are typically set by audiologists, surgeons or other health care professional around the time that the cochlear implant is implanted in the recipient, or after allowing time for healing or adjustment to pass following implantation of the cochlear implant in the recipient.